package com.example.demo;

import java.util.HashSet;

public class Test {


    public static void main(String[] args) {
        HashSet<Object> set = new HashSet<>();
        set.add(new String("hsp"));
        set.add(new String("hsp"));
        set.add(new Dog());
        set.add(new Dog());
        System.out.println(set);
    }

}
